There are fatwas put out there by some scholars that state "martyrdom bombings" are not a form of suicide, and therefore are permitted. Usually the only caveat is that access to conventional arms suchs as airplanes, bombs, missiles, tanks, must not be available first. These are the fatwas followed by those who do suicide bombings.
Obviously there would be fitwa of this type. No doubt, these fisadis have backing of ulema-e-sue who are ulema of this Shaitanic cult. They would obviously defend this Shaitanic cult religion and their actions, as their own beliefs are Shaitanic too.
Anyhow, suicide or Khudkushi means ... killing oneself intentionally and that could be done by any means. If a person acts with intention of killing himself than that action is suicide, regardless of that person lives or die. Intention before getting killed is important. As long as there is an iota bit of chance in the belief of the person (rightly or wrongly) that his initiated action may not kill him and he might live, than that action can be classified as not suicide even though it may look like suicide to others. But there is no chance that a person blowing himself could not be called suicide.